- btrfs_drop_extent_cache(inode, start, start + len - 1, 0);
+ /*
+ * Ok if the extent map we looked up is a hole and is for the exact
+ * range we want, there is no reason to allocate a new one, however if
+ * it is not right then we need to free this one and drop the cache for
+ * our range.
+ */
+ if (em->block_start != EXTENT_MAP_HOLE || em->start != start ||
+ em->len != len) {
+ free_extent_map(em);
+ em = NULL;
+ insert = true;
+ btrfs_drop_extent_cache(inode, start, start + len - 1, 0);
+ }